The present invention relates generally to modular construction techniques for erecting multi-story residences, and more specifically to an improved floor/ceiling construction for such modules having an enhanced fire rating.
It is a growing trend to construct multi-story residential buildings, including hotels, apartments, dormitories, classrooms, restaurants and the like using modular units, especially in crowded urban areas where heavy construction equipment has difficulty maneuvering. Modular construction reduces material waste, and since the units are assembled indoors at remote locations, labor costs and working conditions are more closely controlled. Such modules are remotely constructed and assembled, trucked to the building site, then placed in position using a crane. Many modules are as long as 75 feet and are assembled by stacking vertically, side-by-side, end-to-end, thus providing a variety of configurations of the final building design.
Each module has a steel frame including beams and joists, and depending on the application represents one or two apartment units. Walls are conventionally assembled with studs and panels, and windows are installed in the stud frames in a conventional manner. Designers of such modules need to take into account that the ceiling of a lower module becomes part of the floor/ceiling assembly when combined with the floor of the next higher module. In many cases, the floors of the modules are poured concrete having a weight as much as 40 pounds per square foot (psf) and a 3-inch thick layer. One drawback of conventional modules is the weight, of which the poured concrete floor is a significant contributor. Heavier modules are more expensive to ship by truck to the site, and are more difficult to raise into position. Also, the design of conventional modules is constrained due to a significant amount of module height being allotted to the junction of two adjacent vertically stacked units.
Thus, there is a need for an improved modular building unit which addresses the drawbacks listed above.